Various elastomers such as ethylene-propylenediene terpolymer (EPDM) and styrene-butadiene copolymer have been utilized for many years in applications requiring a sealing contact between the elastomer and another object, such as in glass run channels which are positioned in the window frames of automobile doors to provide a seal between the window frame and the glass.
The elastomer utilized in glass run channel applications generally is flexible to provide a good seal of the elastomer against the window glass without the application of excessive force, and must also display good weatherability properties. However, most suitable flexible elastomers typically lack the low-friction, abrasion or wear-resistant properties necessary for ease of travel of window glass within the glass run channel and long life of the glass run channel itself, respectively.
Therefore, low-friction, wear-resistant coatings for glass run channel have been developed which are applied to the elastomeric substrate usually as solvent-based sprays, or which are applied to the substrate after surface treatment of the substrate with a primer, adhesive, or the like. However, environmental concerns directed to the toxicity and volatility of such solvent-containing materials, and EPA limits on organic solvent emissions, have created the incentive for the manufacture of glass run channel having a solventless or high solid, low-friction, abrasion resistant coating.
Moreover, it has heretofore been difficult to obtain the necessary strong adhesion between such low-friction wear-resistant coatings and the substrate material such as EPDM. For example, EPDM has a low surface energy so wetting is difficult. In addition, EPDM has a low concentration of reactive groups, that is, it contains few carbon-carbon double bonds which makes chemically bonding thereto difficult. Methods which have been used to improve adhesion to EPDM include surface treatments such as flame, ozone, and chlorination. Such surface treatments typically raise the surface energy of the EPDM to levels closer to that of common coatings resulting in improved adhesion. However, such surface treatments are costly and complicate the manufacturing process for applications such as glass run channel. Another method used to improve adhesion has been the application of the aforementioned primer layers. Such layers provide intermediate surface energy between the substrate and coating for relatively good adhesion to each. However, this method also increases cost and normally requires the use of additional solvent, which is undesirable, as discussed above.
As mentioned above, low friction and abrasion resistance also are requirements for glass run channel coating materials. The base polymer in such coatings contributes much of the low-friction and abrasion-resistant properties. Thus, low-friction rubbers such as polyurethanes are generally regarded as good base polymers for coatings. However, in most cases, polyurethanes must be applied to an EPDM elastomer which has been either surface treated or primer coated to achieve good adhesion therebetween.
In addition, many prior coatings contain additives to lower friction and increase abrasion-resistance. Polytetrafluoroethylene (PTFE or Teflon.RTM.) particulates and silicone fluids are conventional additives for friction reduction and may also be useful for improving abrasion-resistance. Although useful in selected coatings, in many cases it is preferable to avoid using such PTFE and silicone additives. More specifically, in certain instances, PTFE particles tend to agglomerate thus reducing their effectiveness, and silicone fluids often are too incompatible with coating materials and phase separate. In addition, silicone fluids sometimes cause poor adhesion between the coating and the substrate. Moreover, silicone fluids in solvent-based formulations may by contact or by dispersion of fine particles in the atmosphere contaminate other unrelated areas of a manufacturing plant and adversely affect adhesion in certain products.
U.S. Pat. No. 3,904,470 to Fukuki et al relates to a method for bonding rubber to plastics by contacting a vulcanized shaped structure of an ethylene/propylene copolymer rubber on an ethylene/propylene/diolefin copolymer rubber with a polyolefin plastic at a temperature above the softening point of said polyolefin plastic, said vulcanized shaped structure consisting of a blend of (i) 60 to 97 percent by weight of an ethylene/propylene copolymer rubber having an ethylene content of 40 to 85 mole percent or an ethylene/propylene/diolefin copolymer rubber having an ethylene content of 40 to 85 mole percent and 0 to 100 percent, based on the weight of the copolymer rubber, of a rubber component other than the above copolymer rubbers and a butyl rubber, and (ii) 3 to 40 percent by weight of specific crystalline polyethylene or polypropylene plastic.
U.S. Pat. No. 3,962,018 to Costemalle et al relates to a multilayer composition prepared by a process comprising applying an intimately mixed blend of a thermoplastic polyolefin and an elastomer to the surface of an elastomer and bonding said blend to said surface by heating and application of pressure. Thus a film of the intimately mixed blend may be applied to the surface of the elastomer. Also, a motor-car door seal can be produced by extruding to the desired profile the intimately mixed blend of thermoplastic polyolefin and elastomer so as to form the base foot and bonding the elastomer seal to the extruded section.
U.S. Pat. No. 4,076,891 to Yardley et al relates to a method of producing a molded plastic rubber composite comprising injection or transfer molding a substantially linear crystalline low pressure solution olefin polymer so that it is brought, in a molten state, into contact with a prevulcanized rubber component containing up to 70 percent by volume of a rubbery olefin polymer. The plastic-rubber composite produced by this method may be used in applications in which hitherto rubber-metal composites have been used, for example valve diaphragms, tire valve bodies, shock absorbers, engine mountings, vibration dampers, compression springs, torsion bushes, flexible drive couplings, etc.
U.S. Pat. No. 4,090,906 to Zoller relates to a method of making a trim strip comprising the extrusion of a vinyl material to form a body which is so shaped that it can be confined in a peripheral slot in a roll, thereby to permit substantial pressure to be applied on the extruded body and a decorative strip by a mating roll. The top portion of the extruded body has side extensions which are supported by the edges of the recessed roll; thus, substantial pressure can be applied on the entire top of the decorative surface strip and the body to produce a adhesive bond or a bond by heat sealing. After the body is cooled, it is advanced through a number of aligned milling cutters to machine aligned recesses in the sides of the body to produce a retention cutout. After being machined to depth, the trim strip is advanced through a pair of grinding wheels to accurately form and space the recesses. During the extruding operation, a coated wire may be embedded within the body in the conventional manner.
U.S. Pat. No. 4,169,180 to McDonagh relates io to a laminate which is useful as a construction material. It comprises: (1) a base layer of a synthetic resin having inferior weather-proof characteristics; and (2) a protective layer of a crosslinked acrylate and/or methacrylate/crosslinked styrene-acrylonitrile/uncrosslinked styrene-acrylonitrile polymer composition attached to the base layer. The laminate can be used as a material for siding, gutter systems, downspouts, soffit and fascia systems, shutters, window casings and the like.
U.S. Pat. No. 4,184,000 to Denman relates to a coupling element comprising elongated thermoplastic strip material structured to provide that, on application thereto of heat in the range from about 300.degree. F. to about 500.degree. F. the outer portion thereof becomes fluidly adhesive, and is particularly adapted thereby to quickly form a ready bond and a clean seal between different materials, especially between glass and metal parts. While under the application of heat in the range specified, the outer portion of the element becomes fluidly adhesive, the inner or core portion of the element retains, as originally provided, an essentially stable form which accommodates and conforms to the contour of an applied load. On self cooling in place the strip coupling device provides a bond and seal between parts of unlike materials. In preferred embodiments and applications the invention provides for an installation of a window, windshield or like unit. Elements of the invention are reversible. Once an element is in place and serving as a bond, if subjected to heat in the prescribed temperature range of 300.degree. F. to 500.degree. F., the outer portion of the element becomes fluid while the stability of the core thereof is maintained. This enables that the element may be removed from between the parts for which it formerly served as a bond.
U.S. Pat. No. 4,198,983 to Becker et al relates to a catheter, preferably a balloon-type catheter, which is disclosed in which the catheter shaft is made of a thermoplastic material and thus may be extrudable, the shaft consisting essentially of (a) from 40 to 70 percent by weight of an elastic composition which comprises: from 50 to 99.5 percent by weight of a block copolymer having thermoplastic rubber characteristics with a central, rubber polyolefin block and terminal blocks of polystyrene, and optionally including up to about 45 percent by weight of polypropylene, plus from 0.5 to 10 percent by weight of a crosslinked organic silicone elastomer; and (b) from 30 to 60 percent by weight of a hydrophobic oil-type plasticizer to provide the desired degree of softness of said elastic composition.
U.S. Pat. No. 4,292,355 to Bonis relates to a moisture-impervious plastic container thermally formed from a coextruded sheet including a layer of polypropylene directly adhered to a layer of butadiene-styrene polymer.
U.S. Pat. No. 4,467,061 to Yamamoto et al relates to a polyolefin composition with an improved weather resistance, which comprises a polyolefin blended with (1) a benzotriazole compound, (2) a heterocyclic hindered amine compound and (3) a phenyl benzoate compound or nickel complex compound.
U.S. Pat. No. 4,537,825 to Yardley relates to a method of making a bonded composite of (i) a thermoplastic elastomeric blend of vulcanized EPDM particles not more than 50 microns in size disposed in a thermoplastic linear crystalline polyolefin continuous phase, with (ii) a vulcanized EPDM or EPM rubber composition containing less than 50 percent (preferably 5 percent to less than 40 percent by volume of rubber), comprises fusing the thermoplastic elastomeric blend and solidifying it in contact with the vulcanized rubber composition in the absence of an adhesive interlayer. Preferably the blend is extruded onto the vulcanized rubber composition. Preferably the linear crystalline polyolefin in the thermoplastic blend has a melt flow index of at least 0.25 when measured according to the test conditions ASTM D1238-65T and is selected from polypropylene, propylene copolymers, high density polyethylene and high density ethylene copolymers.
U.S. Pat. No. 4,600,461 to Guy relates to an apparatus and process for producing an extruded plastic material product which consists of an inner foamed thermoplastic cellular core and an outer non-porous thermoplastic skin extending along at least one side of the core. In the process, a foamable thermoplastic material is extruded through a first die outlet to produce a foamed thermoplastic material. After exiting the die outlet, a film of non-porous thermoplastic material is applied along at least one side of extruded foamed material. Next, the extruded foamed material and the non-porous film is fed through a forming die which shapes and seals the materials into the desired cross-section shape.
U.S. Pat. No. 4,676,856 to Shigeki et al relates to a weather strip for a vehicle which has a channel-shaped base portion having a U-shaped cross section and provided with retaining lips for retaining a flange of a vehicle body, a seal portion integrally projecting from an outer surface of the base portion, and a core member made of synthetic resin and having a U-shaped cross section, which is embedded in the channel-shaped base portion. The method for producing such a weather strip as described above includes the steps of extruding a strip-shaped thermoplastic synthetic resin sheet having stress concentrating portions which are broken when bending stress is applied thereto, with rubber material to obtain an extruded body, heating the obtained extruded body for curing the rubber material thereof, applying bending stress to the cured extruded body for separating the core member in the stress concentrating portion and bending the separated core member with the rubber material to have a U-shaped cross section.
U.S. Pat. No. 4,698,193 to Bernitz et al relates to a method and apparatus for producing sealing strips and similar profiled strips of rubber and rubber-like elastomers. Rubber-like profiled sealing strips for window or door openings are frequently provided with overlay strips to facilitate installation, to enhance the relative movements, or for aesthetic-visual reasons. The material of these overlay strips generally differs considerably from the material of the base main strip. The manufacture of such two-material profiles can be undertaken in a single extrusion step by joining and directly combining a prefabricated overlay strip with the main strip in the extrusion head of an extrusion press, where the shape is provided for the profiled strip. By stretching the overlay strip, the adhesion of the latter to the main strip is improved.
U.S. Pat. No. 4,701,376 to Hermann et al relates to a profiled rubber strip seal for bordering window and door openings. To simplify installation, or to promote relative movement between the strip and windowpanes, such seals are provided with overlay strips of friction-reducing material, especially synthetic materials that contain fluorine. To provide favorable conditions for satisfactory bonding between the overlay strips and the main strip, and also to make it possible to use difficult to handle materials, the elastomeric mixture of the main strip is altered by including therein silicic acid.
U.S. Pat. No. 4,833,194 to Kuan et al relates to blends of crystalline and amorphous polymers which are utilized to form uncured thermoplastic elastomer compositions which have good properties such as processability, tensile strength, tear strength, good weatherability, good friction, and especially low deformation at high temperatures as about 180.degree. F. The thermoplastic elastomer composition contains amorphous ethylene-propylene type rubber, crystalline ethylenepropylene type rubber, and crystalline olefins such as polyethylene. The crystalline polymers generally impart the necessary thermoplasticity for melt processing, and the like.
European Patent Application 0 325 573 relates to shaped articles, such as coatings for wire and cable which are prepared by crosslinking compositions which are mixtures of (A) a polyolefin containing hydrolyzable silane groups and (B) elastoplastic blends of particles of rubber compounds dispersed in a continuous phase of thermoplastic polymer compatible with (A), wherein the rubber compound is at least partially cured.